v2/v3 clear/ssl/tls

Hi!
Could somebody explain me, which port is used to
tls, if I start up a slapd with the "allow bind_v2"
in the config, and with the -h "ldap:/// ldaps:///"?
On tcp/389 there's the LDAPv2 and v3 without any
crypting,
on tcp/636 there's LDAPv3 with StartTLS request,
and LDAPv2 ower SSL.
Am I something misunderstanding?
ldapsearch -x -H 'ldaps://..../' uses StartTLS,
even if I put `-P 2' to the command line. Is it
right? Could You explain me the right thing?
--
bSanyI